It took more than a century to build and was designed over time by Donato Bramante, Giuliano da Sangallo, Fra Giocondo, Raffaello Sanzio da Urbino, Baldassare Peruzzi, Antonio da Sangallo the Younger, and Michelangelo.

Michelangelo's contribution to the basilica was the greatest of them. He was the only architect who worked on it whose plans were continued without significant changes after his death.

In the Catholic Tradition, the Basilica is believed to have been built upon the burial site of Christ’s Apostle Saint Peter. Pope’s have been interned in the Basilica since the early Christian era and a church has existed on the site since the 4th century. It is one of the four Major Basilicas, all of which are in Rome. Built between 1506 and 1626, St. Peter’s Basilica stands as one of the largest churches in the world and one of the holiest shrines and greatest churches in Christendom.

The Old and the New

In ancient Roman times one of the 12 Apostles, Saint Peter, was crucified in Rome by the order of Emperor Nero in 64 AD. Some years after his death a shrine was built upon his burial site which was outside the Roman Circus on what is now called Vatican Hill. Several centuries later in 318 AD, the Emperor Constantine I ordered the construction of a Church on the site. Now known as the Old St Peter’s Basilica this church stood from the 4th until the 16th century before the New St Peter’s Basilica was built on the same site to replace it.

The Old St Peter's Basilica stood for many centuries and was an important Christian holy site. By the 15th century, the old basilica was in a state of disrepair. Plans for changes to the old basilica were made during the reign of Pope Nicholas V. Substantial materials had been transported for this purpose including stone taken from the ancient Roman Colosseum. However, Nicholas V died while little had been done and the reconstruction did not go ahead as intended.

Around 50 years later in 1505, Pope Julius II made the decision to tear down the old basilica and erect a completely new one upon the same site. Julius II had commissioned Michelangelo to design and sculpt his own tomb, which would reside in St Peter’s Basilica. Including Pope Julius II, the construction of the new basilica would occur over the course of the reign of 21 Pope’s in total.

Architecture For the New St Peter’s Basilicas

For such a prestigious project many architects sought the honor and put forward plans for a new basilica. Several of these designs can still be found today at the Uffizi Gallery in Florence. The design settled upon was that of Donato Bramante. Known for Renaissance architecture in Milan and Rome, his design would become the basis for the later work on the basilica by Michelangelo.

The dome became one of the most important aspects of the design for the basilica. Every architect that worked on the new basilica called for a dome to rival that of the ancient Roman Pantheon and the Cathedral of Florence. The design of the dome that would top the basilica called for it to be supported by four large pillars, whereas that of the Pantheon is supported by a continuous wall.

Pope Julius II died in 1513, Giuliano da Sangallo, Fra Giocondo, and Raffaello Sanzio da Urbino (Raphael) replaced Donato Bramante. By 1515 Sangallo, Giocondo, and Bramante had died, leaving Raphael to continue the work. Raphael’s design called for a great extension of five bays added to the nave compared to Bramante’s original plan. The basilica would have been significantly longer had this been carried out. While Raphael died in 1520 his plans were maintained by his successor Baldassare Peruzzi. Complications such as the sack of Rome in 1527, meant that by the time of his death in 1536 this plan had not been implemented.

Antonio da Sangallo the Younger proceeded to take over the work at this point. His primary effort was to strength the constructions of Bramante as they had begun to weaken over time. Combining aspects of the previous plans, Sangallo fashioned his own more elegant design. Shortening the nave, thereby adapting Raphael's plan, was a large part of his own design. 10 years after the death of Raphael, in 1546, Sangallo the Younger also died. Leaving his designs unfulfilled but having carried out important maintenance of the work done by his predecessors.

Michelangelo’s Work on the Basilica

After the passing of yet another architect, Michelangelo was not the first choice of the reigning Pope Paul III, whose preferred architect Giulio Romano had died in late 1546. Jacopo Sansovino was also asked, but he refused to leave Venice to work In Rome. Following these complications, Michelangelo was pressured to take on the job. It was later found in his writings that he said: "I undertake this only for the love of God and in honor of the Apostle.".

Michelangelo took over the construction conditionally, desiring the freedom to accomplish the project as he thought necessary. With this artistic freedom, his designs and their implementation went on to make him the primary designer of the basilica as it exists to this day. In taking up the role of superintendent (Capomaestro) of the construction, Michelangelo had access to all of the previous design plans for the new basilica. All of the previous designers had called for a large dome adorned with a Greek or Latin cross.

The desire for a large dome could draw inspiration from both ancient Rome and Renaissance Italy. Far more recent than the Pantheon of antiquity, in 1436 Filippo Brunelleschi had built the powerful dome of Florence Cathedral. Brunelleschi was one of the founders of the Renaissance. Matching the splendor of Brunelleschi's dome had been envisioned by every architect who worked on the new basilica.

Using the ideas of the previous architects and his own coalesced into a visionary design that brought together the distinctiveness of Bramante’s original design and all of the later plans. The eastern end of the New St Peter’s Basilica with its monumental dome was the centrifugal point of Michelangelo’s work and his most distinct contribution. The dome remains the tallest of its kind in the world today. While he lived Michelangelo only saw to the construction of the base of the dome called the Tamburo.

At the age of 88 years old, Michelangelo died in 1564. Unlike the previous architects that worked upon the new basilica, Michelangelo’s work was intended to continue unchanged. His assistant Jacopo Barozzi da Vignola was left to carry on the work in his stead and the reigning Pope, Pius V, assigned Giorgio Vasari to ensure that the work was carried out in accordance with the plans of Michelangelo.

However, work progressed slowly and Pope Sixtus decided to commission Giacomo Della Porta to oversee the completion of the work in 1585. The speed of construction increased greatly although Sixtus was Pope only for a short time. A number deal of sketches of both general and minute detail had been left by Michelangelo. Porta largely adhered to what had been laid out by Michelangelo, mostly making alterations of a more cosmetic nature. The one major change that Porta oversaw was the raising of the outer dome higher over the inner one.

It is unknown if the hemispherical shape of the dome was Michelangelo’s original intention or if it was changed from an ovoid dome at the behest of Porta. Sketches and models from the time of the construction present mixed representations of the dome. The dome was completed in 1590, it would still be several years before the basilica reached completion. After more than a century, construction ended in the 1600s and the New St. Peter’s Basilica was consecrated in 1626.

Michelangelo's Legacy

Michelangelo is perhaps the most famous artist of the late Renaissance, responsible for many works of art featured in the Sistine Chapel, Laurentian Library, and St Peter’s Basilica. Michelangelo completed two famous works on the Sistine Chapel early in his life, the Sistine Chapel ceiling and The Last Judgement, a fresco.

Prior to his work on the New St Peter’s Basilica, the Pope Julius II commissioned him to paint the ceiling of the Sistine Chapel. The ceiling depicts scenes from the Book of Genesis in the Old Testament. In order to paint the high ceiling, Michelangelo had to devise his own scaffolding and work under difficult conditions standing upright for his work. A fresco painting is painted upon fresh or damp plaster, the plaster dries and sets the paint upon the wall.

Also in the Sistine Chapel is The Last Judgement, it covers the altar wall and like the ceiling, it is a fresco. Michelangelo painted The Last Judgement 25 years after he had painted the ceiling of the Sistine Chapel. It took four years of work for the piece to be finished. Michelangelo’s extensive work for the Vatican prior to his commencement of work on the St Peter’s Basilica highly commended him to that design and his creation was one of the most brilliant works of the Renaissance.

Michelangelo’s most famous sculptures are Pietà and David. Pietà depicts Jesus after his crucifixion, with the Virgin Mary. Pietà was installed in the St Peter’s Basilica and remains there to this day. It is the only work of his art that Michelangelo personally signed. David, named for the biblical David, resides in the Florence Cathedral.

Where the New St Peter’s Basilica is concerned, Michelangelo’s legacy is the dome at the chancel end of the basilica, it is the tallest in of its kind in the world. He did not live to see its completion, which was overseen by Giacomo Della Porta and Domenico Fontana by 1590. But during his life, his plans for the basilica became so advanced and were respected enough that major changes were not made while efforts to stick to his designs were.

The work of Michelangelo influenced art and architecture for centuries after his death. The St. Peter’s basilica inspired the domes of the Capitol building in Washinton D.C and Saint Paul’s in London. He was one of the longest-lived artists of the late Renaissance, so much so that his assistant Giorgio Vasari published a biography of Michelangelo while he still lived. His work has remained a great influence upon artists and architects for more than five centuries now and will be revered as long as his works still stand.

St Peter's Basilica is an extraordinary architectural project within Vatican City.

This key commission was given to several leading Renaissance engineers at different times over a period of many years. Each contribution can still be seen in various elements of the completed building, and Michelangelo's influence was one of the most significant.

Michelangelo officially began work on the Basilica in 1547 and took existing plans and went about impressing his own style and creativity to take them further. The importance of this building to the religious elements of Italy and the Vatican City meant that only the best sculptors and architects would be considered to work on it, and that anyone in that field would take the opportunity without a second thought.

Many focus on the architecture work on the outside of the building, such as it's large dome, but those who get to actually visit this location will stand in awe at the items to be found within the Basilica itself.

Pieta is just one of the incredible masterpieces to be found housed here, but there is also individual detailing across the walls and ceiling which is enough to excite just by itself. Pieta is just one of the few examples of Renaissance art considered good enough to be given the priviledge of being displayed in this famous building, and also seems appropriate considering Michelangelo's involvement with both.